Pongo's ecological diversity from dental macrowear analysis

Area of Science:

• Primate Paleontology
• Dental Anthropology
• Zoology

Background:

• Orangutans (Pongo pygmaeus, Pongo abelii, Pongo tapanuliensis) inhabit Borneo and Sumatra, primarily feeding on fruits.
• Ecological studies indicate dietary differences, with Pongo pygmaeus consuming more low-quality foods like bark than Pongo abelii.
• Investigating geographic variations in dental macrowear can reveal insights into feeding ecology and diet adaptation.

Purpose of the Study:

• To investigate geographic variations in molar macrowear patterns between Bornean (Pongo pygmaeus) and Sumatran (Pongo abelii) orangutans.
• To determine if observed dietary differences correlate with distinct dental wear patterns.

Main Methods:

• Analysis of second mandibular molars from 58 orangutan specimens.
• Utilized dental topographic measurements including occlusal relief index, dentine exposure, and enamel wear.
• Employed the occlusal fingerprint analysis method to assess macrowear patterns.

Main Results:

• No statistically significant differences were found in most molar macrowear variables between Pongo abelii and Pongo pygmaeus.
• Pongo pygmaeus molars exhibited slightly flatter occlusal morphology and larger crushing areas, but these differences were not significant.
• A greater variability in molar wear was observed in Pongo pygmaeus compared to Pongo abelii.

Conclusions:

• The similarity in molar macrowear suggests overlapping long-term diets, predominantly ripe fruits, for both orangutan species.
• Dental macrowear reflects cumulative lifetime wear, potentially obscuring short-term or seasonal dietary shifts.
• Future research integrating micro- and macrowear analysis could provide a more comprehensive understanding of primate dental ecology.